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A182262
Least prime p that 6^n - p is prime.
1
3, 5, 5, 5, 17, 7, 17, 7, 7, 7, 59, 19, 17, 13, 7, 19, 137, 13, 19, 7, 23, 97, 19, 89, 17, 223, 29, 109, 5, 19, 5, 59, 197, 5, 17, 307, 59, 83, 109, 157, 19, 23, 43, 109, 103, 7, 23, 19, 7, 269, 43, 13, 5, 67, 89, 83, 479, 53, 53, 383, 7, 83, 113, 37, 5, 23
OFFSET
1,1
LINKS
EXAMPLE
For n=3 p=5 is the least prime that 6^3-p is prime (211).
MAPLE
f:= proc(n) local t, p;
t:= 6^n;
p:= 2;
do
p:= nextprime(p);
until isprime(t-p);
p
end proc:
map(f, [$1..100]); # Robert Israel, Nov 05 2020
MATHEMATICA
f[n_] := Block[{p = 2}, While[! PrimeQ[6^n - p], p = NextPrime[p]];
p]; Array[f, 60]
PROG
(PARI) a(n) = my(p = 2); while(!isprime(6^n-p), p = nextprime(p+1)); p; \\ Michel Marcus, Mar 23 2016
CROSSREFS
Cf. A013607, A059614 (n such that a(n)=5).
Sequence in context: A120133 A088961 A079090 * A273085 A329765 A258714
KEYWORD
nonn
AUTHOR
Mateusz Szymański, Apr 21 2012
STATUS
approved